fix: Lazy load git repo and only run module if not disabled (#306)

A couple of optimizations are done in this PR. One, we now will check config ahead of time to see if a module is disabled before running any module code. Also, we won't try to discover a git repository unless the module requests access to it.

1 files changed, 17 insertions, 24 deletions

diff --git a/src/modules/git_state.rs b/src/modules/git_state.rs
index 8d242b0ca..c26a6007b 100644
--- a/src/modules/git_state.rs
+++ b/src/modules/git_state.rs
@@ -1,6 +1,6 @@
 use ansi_term::Color;
-use git2::{Repository, RepositoryState};
-use std::path::Path;
+use git2::RepositoryState;
+use std::path::{Path, PathBuf};
 
 use super::{Context, Module};
 
@@ -9,11 +9,12 @@ use super::{Context, Module};
 /// During a git operation it will show: REBASING, BISECTING, MERGING, etc.
 /// If the progress information is available (e.g. rebasing 3/10), it will show that too.
 pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
-    let mut module = context.new_module("git_state")?;
+    let mut module = context.new_module("git_state");
 
-    let repo_root = context.repo_root.as_ref()?;
-    let mut repository = Repository::open(repo_root).ok()?;
-    let state_description = get_state_description(&mut repository);
+    let repo = context.get_repo().ok()?;
+    let repo_root = repo.root.as_ref()?;
+    let repo_state = repo.state?;
+    let state_description = get_state_description(repo_state, repo_root);
 
     if let StateDescription::Clean = state_description {
         return None;
@@ -79,8 +80,11 @@ static AM_OR_REBASE_LABEL: StateLabel = StateLabel {
     message_default: "AM/REBASE",
 };
 
-fn get_state_description(repository: &mut Repository) -> StateDescription {
-    match repository.state() {
+/// Returns the state of the current repository
+///
+/// During a git operation it will show: REBASING, BISECTING, MERGING, etc.
+fn get_state_description(state: RepositoryState, root: &PathBuf) -> StateDescription {
+    match state {
         RepositoryState::Clean => StateDescription::Clean,
         RepositoryState::Merge => StateDescription::Label(&MERGE_LABEL),
         RepositoryState::Revert => StateDescription::Label(&REVERT_LABEL),
@@ -90,13 +94,13 @@ fn get_state_description(repository: &mut Repository) -> StateDescription {
         RepositoryState::Bisect => StateDescription::Label(&BISECT_LABEL),
         RepositoryState::ApplyMailbox => StateDescription::Label(&AM_LABEL),
         RepositoryState::ApplyMailboxOrRebase => StateDescription::Label(&AM_OR_REBASE_LABEL),
-        RepositoryState::Rebase => describe_rebase(repository),
-        RepositoryState::RebaseInteractive => describe_rebase(repository),
-        RepositoryState::RebaseMerge => describe_rebase(repository),
+        RepositoryState::Rebase => describe_rebase(root),
+        RepositoryState::RebaseInteractive => describe_rebase(root),
+        RepositoryState::RebaseMerge => describe_rebase(root),
     }
 }
 
-fn describe_rebase(repository: &mut Repository) -> StateDescription {
+fn describe_rebase(root: &PathBuf) -> StateDescription {
     /*
      *  Sadly, libgit2 seems to have some issues with reading the state of
      *  interactive rebases. So, instead, we'll poke a few of the .git files
@@ -107,18 +111,7 @@ fn describe_rebase(repository: &mut Repository) -> StateDescription {
 
     let just_label = StateDescription::Label(&REBASE_LABEL);
 
-    let dot_git = repository
-        .workdir()
-        .and_then(|d| Some(d.join(Path::new(".git"))));
-
-    let dot_git = match dot_git {
-        None => {
-            // We didn't find the .git directory.
-            // Something very odd is going on. We'll just back away slowly.
-            return just_label;
-        }
-        Some(path) => path,
-    };
+    let dot_git = root.join(".git");
 
     let has_path = |relative_path: &str| {
         let path = dot_git.join(Path::new(relative_path));